Wide-belt grinding machine,more particularly for working sheet metal



June 1970 L L E. EICH' ET AL 3,516,208

WIDE-BELT GRIHDING MACHINE, MORE PARTICULARLY FOR WORKING SHEET METAL Filed Nov. 13. 1967 s Sheets-Sheet 1 INVENTORS June 23, 1970 Filed Nov. 13. 1967 E. EICH ET AL 3,516,208 WIDE-BELT GRINDING MACHINE, MORE PARTICULARLY I T METAL FOR WORKING SHEE 3, Sheets-:Sheec 2 I8 A 14 I! Ila . INVENTORS [0M 0 [/V/ H67 6679/1/6 I QZMM W June 23, 1970 E E|H ETAL 3,516,208

WIDE-BELT GRINDIliG MACHINE, MORE PARTICULARLY FOR WORKING SHEET METAL Filed Nov. 13. 196'! 3 Sheets-Sheet 5 IN VEN TORS fDMUA/D [/CH Wad $7M 9% AT/WP/VEVS United States Patent WIDE-BELT GRINDING MACHINE, MORE PARTICULARLY FOR WORKING SHEET METAL Edmund Eich and Heinz Gerner, Coburg, Germany, as-

signors to Werkzeugmaschinenfabrik Adolf Waldrich Coburg, Coburg, Bavaria, Germany, a corporation of Germany Filed Nov. 13, 1967, Ser. No. 682,269 Claims priority, applicatiglzl Gelrmany, Nov. 17, 1966,

,81 Int. Cl. B24b 21/10, 21/04 U.S. Cl. 51-443 5 Claims ABSTRACT OF THE DISCLOSURE A belt grinding machine having two columns interconnected by a cross head and a pair of slides each guided for vertical movement on each of the columns and interconnected by a crossbeam. A hearing arm is rigidly connected to one of the slides and extends generally parallel to the crossbeam and is spaced outwardly from the crossbeam to define a passageway therebetween. A locking member is fixedly secured to the other of the slides and includes means for releasably coupling the locking member to the free end of the bearing arm to rigidity the bearing arm. A pair of rotatable guide rolls are mounted on the bearing arm and support an endless grinding belt. The belt extends through the passageway, the locking member being releasable from the free end of the bearing arm to permit the removal of the grinding belt from the passageway.

The invention relates to a wide-belt grinding machine, more particularly for working sheet metal, consisting essentially of two columns and a bearing arm carrying the guide rolls for the grinding belt and which is fixedly connected at one end to a first slide guided for vertical adjustment on one column of the machine and adapted to be fixed in position thereon and, for the purpose of changing the grinding belt, is disengageably connected to a second slide guided on the second column.

In such known grinding machines, it is necessary that the bearing arm, which carries the guide rolls for the grinding belt as Well as a tensioning and a driving arrangement, be secured to the first slide in self-supporting fashion. To change the endless grinding belt, that is to say, it is necessary to draw the grinding belt off over the free front end of the bearing arm. In particular, in the case of grinding machines having only two guide rolls, there is only a little room available for accommodating the bearing arm, the tensioning device and the guide rolls inside the space enclosed by the endless grinding belt. For this reason, the bearing arm cannot be made rigid to any degree that may be desired. Recourse has been had to an expedient in that, in addition to the main column which carries the first vertically adjustable slide, an auxiliary column carrying a second vertically adjustable slide has been arranged on the other side of the table. This second slide is disengageably connected to the free end of the bearing arm. In this construction, the second slide is disconnected from the free end of the bearing arm for the purpose of changing the belt and, when this is done, the free end of the bearing arm drops, since the support is now wanting at the free end and the entire weight of the bearing arm must be carried by the first slide. This dropping action can be traced back to the bending deformation of the main column and to the guiding play of the first slide. Due to the lowering of the free end of the bearing arm, however, the lower roll, which faces the table receiving the workpiece, is no longer ice exactly parallel to the surface of the table. When the second slide and the free end of the bearing arm are reconnected to one another after the belt has been changed, the parallelism of the lower guide roll with respect to the surface of the table is not set up again in the desired degree and, as a result, exactly parallel grinding cannot be carried out.

The problem underlying the present invention, therefore, is to provide a wide-belt grinding machine of the type mentioned at the beginning which is more rigid in construction and therefore permits a higher working accuracy and also a higher efiiciency of removal. According to the invention, this is achieved in that the two slides are joined by a crossbeam arranged parallel to the bearing arm and at a distance therefrom and the two columns of the machine are connected by a crosshead in manner known per se, one strand of the grinding belt being passed through between the crossbeam and the bearing arm. Subtantially more rigid mounting of the bearing arm is obtained by means of this construction according to the invention. In fact, when the connection between the second slide and the free end of the bearing arm is opened in this construction, there is no change in the total load on the two slides, since they are connected together by way of the crossbeam. The weight of the bearing arm is furthermore borne by both slides and the play which posibly exists in the guiding of the first slide cannot take effect. Consequently, the free end of the bearing arm does not drop any longer or drops only to a substantially smaller extent, so that after the grinding belt has been changed and after the second slide has been reconnected to the free end of the bearing arm, the original state and the original accuracy exist once more. Due to this greater rigidity, it is also possible to obtain higher efiiciencies of removal. Furthermore, the stability and accuracy are also increased in that, instead of the main column and auxiliary column which have heretofore been customarily employed, two equal columns are employed which are connected together by a crosshead in manner known per se after the fashion of a portal grinding machine.

Further details and advantages of the invention are described more fully hereinafter with reference to embodiments thereof which are illustrated in the drawing, in which:

FIG. 1 shows a first embodiment in diagrammatic view;

FIG. 2 is a horizontal section on the line IIII of FIG. 1; and

FIG. 3 shows a second embodiment.

In the drawing, the reference 1 designates the workpiece receiving table, which is mounted for reciprocation on the bed 2 of the machine. Provided on both sides of the bed of the machine are the columns 3 and 4 thereof, which are connected together at the top by a crosshead 5. A first slide 6 is arranged to be vertically adjustable on the column 3 by means of a spindle 7. This slide 6 can be clamped to the column 3 by frictional contact in any desired height position by clamping means which are known per se and are therefore not shown. A second slide 8 is mounted on the column 4 so that it can be adjusted vertically thereon by means of the spindle 9 and can likewise be fixed in position on the said column. The two spindles are driven simultaneously in known manner by a common driving motor 10 which is housed in the crosshead. The bearing arm 11 is fixedly connected to the first slide 6. This bearing arm 11 carries the two guide rolls 12 and 13 for the endless grinding belt 14. Moreover, the bearing arm contains a tensioning device 15, not shown in detail, by means of which the belt tension can be adjusted. The drive is carried out by way of the driving motor 16.

According to the invention, the two slides 6 and 8 are fixedly connected together, or combined to form one piece, by means of a crossbeam 17, this crossbeam 17 being arranged parallel to the bearing arm 11 and at a distance A therefrom. One strand of the grinding belt 14 is passed through between the bearing arm 11 and the crossbeam 17.

So that the grinding belt can be changed, the free end 11a of the bearing arm is disengageably connected to the second slide 8. To this end, a locking member 18 extending approximately over the entire height of the second slide and adapted to be connected to the free end of the bearing arm is advantageously provided on the said second slide, the locking member being adapted to be hinged about the pivot 20 held in the bearing lugs 19. Owing to the fact that the locking member extends approximately over the full height of the slide 8, particularly torsionrigid mounting is achieved and this stiifens the bearing arm additionally as soon as it is connected to the locking member 18. When the connection of the locking member 18 with the free end 11a of the bearing arm is opened, the locking member can be hinged away laterally, as shown in FIG. 2 by the arrowB, and the endless grinding belt can now be drawn off or refitted over the free end 11a of the bearing arm.

Instead of connecting the free end 11a of the bearing arm by means of a locking member adapted to be swung about a vertical pivot, it is also possible if necessary, as shown in FIG. 3 to arrange a horizontally slideable locking member 21 on the second slide 8. In this case, there is provided at the free end of the bearing arm 11' a recess 22 in which the locking member engages in the operative position and is clamped. In the embodiment shown, the locking member has a dovetailed foot and is guided in a corresponding dovetailed guide in the second slide 8'. Accordingly, the recess 22 is also dovetailed. A particularly strong and torsion-rigid connection is also produced in this case between the free end of the bearing arm and the second slide 8. By shifting the locking member 21 in the direction C into the position shown in dash lines, the free end of the bearing arm 11 is released from the slide 8' and the grinding belt can consequently be changed without any impediment.

Although a particular preferred embodiment of the invention has been disclosed above for illustrative purposes, it will be understood that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

The embodiments of the invention in which an exclusive property or privilege is claimed as defined as follows:

1. A belt" grinding machine comprising: two columns, a slide guided for vertical adjustment on each of the columns, said slidesybeing interconnected by a crossbeam, a

4 bearing arm rigidly connected to one of the slides and extending generally parallel to said crossbeam, said bearing arm and said crossbeam being spaced apart to define a passageway therebetween, a locking device fixedly secured to the other slide and including means for releasably coupling the locking device to said bearing arm at a position spaced from the connection of said bearing arm to said one slide to rigidify said bearing arm, a pair of rotatable guide rolls mounted on said bearing arm, an endless grinding belt supported on said guide rolls and having one reach thereof extending through said passageway, said locking device being releasable from said bearing arm to permitthe removal of the grinding belt from said passageway.

2. A belt grinding machine according to claim 1, in which the bearing arm is connected at one end thereof to said one slide and has a free end located adjacent the other slide, said locking device being releasably connected to said free end of said bearing arm.

3.'A belt grinding machine as claimed in claim 2, wherein said locking device is secured to the other of said slides for pivotal movement about a generally vertical pivot axis, said locking member being of substantially the same height as said free end of said bearing arm for strengthening the coupling of said locking device to said free end of said bearing arm.

4. A belt grinding machine as claimed in claim 2, wherein said means for releasably coupling said locking device to said free end of said bearing arm includes a dovetailed foot on said locking device and a dovetailed guide on said free end of said bearing arm and said other of said slides, said dovetailed foot being slideably receivable in said dovetailed guide on said other of said slides and said free end of said bearing arm to releasably couple said locking device to said free end of said bearing arm.

5. A belt grinding machine as claimed in claim 1, wherein said guide rolls are horizontally disposed and vertically spaced and the axes of rotation thereof being located in a common vertical plane.

References Cited UNITED STATES PATENTS 1,308,610 7/1919 Townsend 51-148 1 ,633,552 6/1927 Wells 51135 X 2,423,737 7/1947 Tavano 51-135 2,597,256 5/ 1952 Murray 51148 X 2,714,787 8/1955 Orr 51143 X 2,783,593 3/1957 Hercik 51135 3,354,588 '11/1967 Roehrig 51148 X ROBERT C. RIORDON, Primary Examiner D. G. KELLY, Assistant Examiner 

